Nano-bubble water is currently used for a washing step of semiconductors and for the promotion of the growth of crops. Heretofore, nano-bubbles could be formed only at a low density, it was difficult to maintain presence of nano-bubbles in water for a long time and maintain the effect thereof. Therefore, utilization of nano-bubble water has been limited to use requiring presence of nano-bubbles for a short time such as cleansing of tools and the like.
Injections such as vaccine preparation and the like are largely divided into 2 kinds of single administration type and multiple administration type.
In a single administration type injection, only a single dosage of a drug solution such as a sterilization treated vaccine solution and the like is tightly sealed in an individual vial to prevent bacterial contamination. Since a single administration type injection uses the entire drug solution at one time, addition of a preservative does not need to be considered. However, since the production cost of such single administration type injection is high, use thereof particularly in the developing countries (e.g., prophylactic inoculation of vaccine preparation etc.) is not realistic.
On the other hand, in a multiple administration type injection containing a drug solution such as a vaccine and the like in an amount for several people in one vial, a preservative such as thimerosal, phenoxyethanol, para-hydroxybenzoate, phenol and the like is contained in the drug solution, as a preservative for killing or suppressing growth of bacterium that was mixed during puncture of the injection needle, since it is punctured multiple times through the rubber closure portion of the vial when in use.
Patent document 1 describes that a composition containing ultrafine bubbles and a medicament expresses the effect of the medicament more, and when a medicament is dispersed in aqueous ultrafine bubble solution, a stable dispersion can be obtained without using a surfactant. Example 1 describes ultrafine bubble water at 4.0-8.0×106 bubbles/mL. FIG. 4 describes that ultrafine bubbles are stably present for 300 hr. However, ultrafine bubble water containing ultrafine bubbles at not less than 2.0×108 bubbles/mL and an antibacterial action of the ultrafine bubble water are not described.
Non-patent document 1 describes that nano-bubble water was produced using a nano-bubble generating apparatus (nanoGALF™) and under the conditions of distilled water 4.0 L, bubble water flow rate 4.0 L/min, dissolution pressure 0.3 MPa, 30 min, and the number of nano-bubbles was measured using LM20 (NanoSight) to obtain nano-bubble water with 1.42×108 bubbles/mL. However, nano-bubble water comprising not less than 2.0×108 bubbles/mL of nano-bubbles and an antibacterial action of the nano-bubble water itself are not described. It also describes that the nano-bubble water stably maintains nano-bubbles at 1.0×108 bubbles/mL in water for about 3 days immediately after production, but nano-bubbles disappear when the number of the nano-bubbles is measured after 4 months of storage.